1. Field of the Invention
This invention relates to an electronic camera system in which image information obtained by an image pickup device is electrically processed to be recorded on a recording medium.
2. Description of the Prior Art
There has been developed an electronic still camera using an image pickup member which may be a solid state image pickup device formed of, e.g., charge-coupled devices (CCD), or an image pickup tube. Such a solid state image pickup device or an image pickup tube is also employed in a motion picture camera or a VTR camera. Accordingly, it is theoretically possible to use a single electronic camera both as a still camera and as a motion picture camera. However, in so doing, there are various difficulties as follows.
(1) In the case of a still, the quality of an image is required to be high, while in the case of a motion picture, the quality of the image need not be so high. Accordingly, in the case of an electronic still camera, a quantizer is required to be of large quantization bit number corresponding to the number of tone levels required to obtain an image of high quality, while in the case of an electronic motion picture camera, a quantizer having a relatively small quantization bit number can be used. Further, in the case of the electronic still camera, a great number of picture elements are required and therefore the amount of data for a frame becomes large. Thus, a recording/controlling section must be used which can process such a large amount of data.
(2) When taking still pictures, the shooting rate is no more than three to five frames a second. Therefore the read out speed from the image pickup member may be low. However, in the case of a motion picture, the shooting rate is generally as high as thirty frames a second. This requires a high read out speed from the pickup member.
(3) In an electronic camera, a magnetic recording medium such as a magnetic recording tape is used. When taking a still picture, the magnetic recording tape is caused to run intermittently, while when taking a motion picture, the magnetic recording tape is caused to run continuously.
(4) When taking a still picture, image signals may be simply serially read out from the image pickup device, while in the case of a motion picture, the image signals should be read out in an interlaced fashion or alternatively should be once stored in a buffer memory to be subsequently recorded in an interlaced fashion.
(5) In the case of a motion picture, the recording medium should be of a larger capacity, while in the case of a still picture the recording medium may be of a relatively small capacity.
As can be seen from the above description, it is very difficult to obtain an electronic camera having a recording/controlling section and a recording medium which can satisfy the various requirements for taking both still and motion pictures. Even should such an electronic camera be obtained, it would be very expensive and of very large size and weight, and would be quite inconvenient for practical use.